Mobile broadcast provides broadcast services over a large area, which includes unidirectional One-to-Many (1-to-M) broadcast and bidirectional unicast in a mobile environment. Mobile broadcast covers all the 1-to-M services ranging from the traditional broadcast to the mobile broadcast, and is applied to provide the public with video, audio, multimedia and data services including conditional receiving and interactive data receiving, etc. Mobile broadcast takes the full advantage of the “point-to-multipoint” transmission approach and transmits information to the public via general receivers. Mobile broadcast transmits a great deal of information to user terminals by using asymmetric distribution infrastructure typically.
In a mobile broadcast service, service contents may be distributed to a user terminal in two ways: one way is to transmit the broadcast service contents to the user terminal via a broadcast service unit by a broadcast service distributor; the other way is to obtain the service contents via an interactive service unit by the user terminal. In the prior art, the broadcast service distributor distributes all the contents of service packets to the user terminal via the broadcast service unit or the interactive service unit in real time. Therefore, the service packets transmitted are often oversized in that there are many parts already existing in terminal, which occupy the limited transmission and equipment resources, thus reducing the efficiency of transmission.